The fastening together of pieces, such as two pieces of relatively heavy sheet metal in a building has heretofore been accomplished primarily by the drilling of holes and the using of conventional bolt and nut fasteners, by the use of self-drilling and self-tapping screws, and by using conventional rivets that are separate from the sheet metal. In Knudson U.S. Pat. No. 5,231,748 there is disclosed fastening apparatus for joining two sheet metal pieces using a separate rivet that is positioned in holes in the pieces and has opposed rivet flanges that are flattened against opposed outer faces of the pieces.
A number of attempts have been made to use hand tools to punch and crimp relatively small holes in relatively light gauge metals. Tuttle U.S. Pat. No. 1,176,793 discloses a hand tool comprising a pointed punch and a female die member with a round hole by which aligned holes are formed in the two pieces of relatively thin sheet metal together with punched out continuous or circular projecting portions and then the punch and female dies are reversed and the punched out continuous or circular projecting portions are folded back to form a rivet head to fasten the two pieces together.
Klenk U.S. Pat. No. 3,261,073 discloses a hand operated tool which describes only the operation of perforating at least two layers of relatively thin sheet material as a part of a punching operation. The punch member has at least two circumferentially arranged flat angled faces tapered to a point to cut the material into separate projecting flaps or tabs. The clinching operation is not described.
Ashby U.S. Pat. No. 4,306,511 discloses a pierce and extrusion punch and cooperating die that forms a continuous rivet head in the form of two coaxial flattened tubes.